Process for vulcanizing rubber and products obtained thereby



Patented Jan. 22, 1935 Y 1 I rnooEss Fort The present invention relates to the treatment of rubber with variou sreactionproducts of aldehyde amine condensation products, and particularly to the preparationlof halogen containing aldehyde. amines. The invention is also conclfned with improving the vulcanization-accelerating; power ,of such -,condensation products by treatment withwhalogens or with halogen acids. This case is a division of Serial No. 145, 71$.filed-November 1, 1926, now U. S. Patent No. 1,852,444.

As one illustration of a method of preparing one of these halogen-containingcondensation products, a hydrogen chloride derivative of heptaldehyde aniline may be prepared by dissolving 20 parts by weight of the heptaldehyde aniline in twice its volume of dry ether, and then treating with dry hydrogen chloride gas for about 4 hrs., keeping the reaction mixture cooled with ice. After the mixture has become saturated, the ether may be removed by vacuum distillation, and the excess of hydrochloric acid may be eliminated by passing air through the reac-' tion mixture. The reaction product is a viscous mass having an agreeable smelL' One gram of it will absorb all the iodine in 58.2 cc. of N/lO iodine in benzol. A rubber compound containing 100 parts by weight of rubber, 10 of zinc oxide, 3 of sulphur and .1 part of this hydrogen chloride reaction product will give a tensile strength of 2875 lbs. per sq. in. in 60 minutes vulcanization at 40 lbs. steam pressure. This reaction product may also be prepared by introducing dry hydrogen chloride into the heptaldehyde aniline condensation product directly. One gram of the reaction product prepared in this manner will absorb the iodine in approximately 56.2 ccs. of N/ 10 iodine.

In a further form of the invention the accelerator employed in the treatment of rubber is prepared by shaking 101.6 grams of heptaldehyde-aniline with 117 grams of 36% hydrochloric acid, the mixture being then boiled in an oil bath for about 2 /2 to /2 hrs. under a reflux condenser. The oily layer may be washed several times with an equal weight of water, and it will be observed that the first three wash waters are slightly colored. The fourth, fifth, sixth, seventh, eighth and ninth wash waters show a gain in weight and in addition are deeply colored by some soluble material. Upon acidification of these (fourth to ninth) combined wash waters,

an oil separates out, one gram of which will absorb the iodine in 45.5 cos. of N/10 iodine in i 5 1,988,458 7 I 7 VULCANIZING RUBBER-.ANDr.

. PRODUCTS OBTAINED THEREBY Sidney'M. Cadwell, Grosse Pointe vi'uagetncn; If assignor, by mesne assignments, to United States Rubber Company; New corporation of NewJersey' part of accelerator for 4000 parts of rubber.

York, Ngm: r

a No; Drawing. Original application vNovft antithet- 1,

1926, Serial No. 145,718.", Divided'and'this ap 'plication September 3, 1931, Serial'No. 561,004

benzol., In the. bove-rubber compound 6 part of thisjreaction product will upon vulcanization r0150 minQfa't i0v lbs. steam. pressure, give a tensile strengthjof 3165. lbs. 11 the amount be increased to .25 part of, accelerating product, the tensilestren'gth is about'4165 lbs. in the same time andatthe.sametemperature...

JInstead ofusing.36%'hydrochloric acid exc'ellent. results have been' .-obtaind by,'employ g 33% ,sulphuriciacid in the above-procedure.

Iiisteadbf treating the'derivati've in the'above wash waters with acid, one may treat the above waters with aqueous sodium hydroxide, whereupon oil separates out which has an odor resembling iso nitrile. One gram of this oil absorbs '75 cc. of N/l0 iodine in benzol. .05 of a part 01' this material when used in the formula given above and vulcanized for30' under 40 pounds steam pressure gave a tensile of 3020. .025 of a part of this material when used as above gave a tensile of 2830 after 60' under 40 pounds steam pressure. It will be observed that this is one It is believed that this is the most powerful accelerator that has ever been produced.

It will be observed that the formation of these halogen containing reaction products or derivatives will result in an increase in the accelerating value of the aldehyde amine. The invention is not limited to any particular proportion of aldehyde and amine in the condensation products, but contemplates the use of such condensation products in which the amount of aldehyde or aminemay be varied within the known limits. The invention also aims to include the halogen containing reaction products or derivatives of aldehyde amines in which the aldehyde portion may comprise more than one aldehyde. The condensation products which are utilized herein may be prepared in any desired manner, and as stated above the constituents may be in any suitable proportions, the combination of alder hyde and amine being effected in one reaction or in several reactions in any well-known manner.

The accelerating products of the present invention may be added to rubber on the mixing mill in the usual manner, or may be introduced into solid rubber in any other suitable way, or

into rubber solutions or dispersions including aqueous dispersions of rubber, either artificial .or natural.

Having thus described my invention, what I claim and desire to protect by Letters Patent is: 1. As a new class of compounds suitable for use in the vulcanization of rubber, the products obtained from. treating a preformed heptaldehyde, and aniline condensation product with a strong mineralacid. I

2. As acbmpound suitable for the yulczinization of rubber, the product obtained from treating a preformed heptaldehyde-aniline con-r densation product with hydrogen chloride in the" form of a dry gas, and removing excess hydrogen I 4. As a compound suitable for use in the Volcanization of rubber, the oily .productobtained from refluxing a preformed condensation product of heptaldehyde and aniline ,with hydrogen chloride, washing with "wateniand treatingthe wash water 'with alkaliftoeffect the separation of an oily product therefrom, and'recovering said oily product. ff I 5. Process of' treatlng rubber which comprises fvulcanizing rubber in'the presence of the oily productobtained by'refluxing a preformed con-v densation product of heptaldehyde. and aniline with a strong mineral acid, washing with water and treating the Wash water with acid to effect the separation of an oily product therefrom, and recovering. said oily product. I

6, Process fortreating rubberwhich comprises combining therewith sulphur and a product ob- .tained from treating a preformed heptaldehyde and aniline condensation product with hydrogen chloride, and vulcanizing the rubber.

7; A vulcanized rubber product derived from rubber combined with sulphur and a product obtained from treating a preformed heptaldehyde and aniline condensation product with hydrogen chloride.

8. Process of treating rubber which comprises vulcanizing rubber in the presence of the oily product obtained by refluxing a preformed condensation product of heptaldehyde and aniline with a strong mineral acid, washing with water and treating the wash water with alkali to effect the separation of an oily product therefrom, and recovering said oily product.

'9. The process of treatin'grubber which comprises vulcanizing rubber in the presence of a product obtained from treating a preformed heptaldehyde aniline condensation product with hydrogen chloride in theform of a dry gas, and remo'v'ing excess'hydrogen chloride.

" SIDNEY M. CADWELL. 

